Trical works



(No Model.)

F. B. RAB. ELECTRICAL SWITCH.

No. 437,513. A Patented sept. 30, 1890. 1

v g AMC INEWTL/ UNITED STATES PATENT OFFICE.

FRANK B. RAE, OF DETROIT, MICHIGAN, ASSIGNOR TO THE DETROIT ELEO- TRICALWORKS, OF SAME PLACE.

ELECTRICAL SWITCH.

SPECIFICATION forming part of Letters Patent No. 437,513, datedSeptember 30, 1890.

Application led March 28, 1890. Serial No. 345,694. (No model.,`

To all whom it may concern:

TBc it known that I, FRANK B. RAE, a citizen of the United States,residing at Detroit, lVayne county, State of Michigamhave inventedcertain new and useful Improvements in Electrical Switches, of which thefollowing is a specication.

My invention relates to apparatus for connecting and disconnecting dynamomachines xo to and from their working-circuits, and especiallywhere they are operated in multiple arc or parallel circuit. It is wellknown that when a number of electric generators are connected inmultiple are to feed into the same workingcircuit it is necessary toopen and close the circuits leading to any one generator in a certainpredetermined sequence in order that the currents may pass through thegenerator without danger of injury to the generator. zo Under suchcircumstances, not only are the terminals of the generator connected tothe leading or working circuits, but, in order to maintain thegenerators at substantially a constant potential, they are alsoconnected to 2 5 a neutral conductor, or what is termed in the art abuss-wire, and, as this is usually connected directly to the negativebrush, if perchance the neutral and positive conductors are closedbefore the negative conductor, an 3o abnormal current will ow throughthe armature, which has a tendency to injure or destroy the generator.It has therefore been found necessary under such conditions to close thecircuits to include a generator in 3 5 the series by first closing thenegative circuit before the neutral and positive circuits are closed. Itsometimes happens that, through inadvertence or otherwise with theordinary switches in the circuits, the wrong circuit is 4o closed first,and in order to prevent the possibility of such accidents I have devisedthe switch which forms the subject-matter of this application.

Referring to the accompanying drawings, Figure l is a plan view of theswitch, with a diagram showing one arrangement of circuits of one of aseries of generators feeding into the mains. Fig. 2 is a side view ofthe switch. lVhile the switch maybevariously construct- 5o ed and embodythe principles of my invention, the preferred form is that illustratedin the drawings, in which, upon a suitable base A, of non-conductingmaterial, are mounted three sets of terminalsB B', C C', and D D. One ofeach pair of terminals is connected to the cir- `5 5 cuits, while thecomplementary terminal of each pair is connected to one of the circuitsof the generator G. Thus the terminal B is connected with the conductorM, which we will assume to be the minus. The terminal() is con- 6onected to the neutral or buss Wire, and the terminal D is connected withthe plus or positive wire of the working-circuit, while on the otherhand the terminal B is connected to the generator at the end of thefield-magnet coil F, which is usually placed in series with the armatureof the generator. The terminal C is connected to the brush E', which maybe called the negative brush, and the terminal D is connected with thebrush E, which 7c may be termed the positive brush of the generator.Also mounted upon the base, preferably at its end, is a plate H, havinglugs h, in which is pivoted the'v arm I, having a suitable handle J foroperating it. This handle is provided with suitable independentconnecting-pieces K K K2, arranged transversely to the handle andinsulated therefrom in any suitable manner, as -by the insulatingmaterial L. The ends of the connect- 8o ing-pieces are preferably bentdown, as shown at k, so as to form knife-edges, and the terminals B O Dare preferably formed with two upturned edges b b', forming a socket forthe reception of the knife-edges. It will be seen that in thisarrangement the connector K, being nearer the pivotal point of the leverI, will come in contact with its correspondingl terminals before theconnector K will contact with its terminals, and this will complete its9o contact before the connector K2. In this way simply depressing thehandle will close the circuits in a certain predetermined order, andwhen used in the connection illustrated in Fig. l all danger of burningor injuring the generator is avoided, as the circuits must be closedproperly. The same may be said upon opening the circuits. The connectorK2 will break the positive circuit before the negative circuit isbroken, and in order to switch in roo and out of circuit any one of aseries of gener ators it is only necessary to move the singleswitch-handle and the circuits will be broken or closed properly.

Another advantage is accomplished in the use of the switch illustratedresulting from the transversearrangement of the connecting-pieces on thearm of the switch and the use of the two terminals to each circuit. Inthis lconstruction `each circuit isl broken or closed at two pointssimultaneously, and thereby the danger of sparking or arcing at themoment of rupture is avoided to a great extent.

While I have described the preferred embodiment of my improved switchand its use in connection with a number of generators feeding into thesame circuit, it is evident that the switch may be lused in many otherconnections with advantage and accomplish the same results, and Itherefore do not limit myself t'o the precise construction andarrangement showin- What I claim is- I. A switch having threeindependent sets of terminals and an arm carrying three independentconnectingpieces arranged to contact with the sets of terminalssuccessively, substantially as described.

2; A switch consisting of an insulated basepiece having three sets ofterminals mounted thereon and an arm pivoted thereto having threeconnecting-pieces mounted thereon but linsulated therefrom, and arrangedto make Contact withthe terminals successively, substantially asdescribed.

3. A three-point switch consisting of abasepiece having three sets ofterminals mounted thereon, each terminal having two upturned edgesforming a socket between them, and an arm pivoted to said piece andhaving three connectors mounted thereon. but Vinsulated therefrom, eachconnector having downwardly-turned ends adapted to engage the terminalssuccessively, substantially as described.V

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

FRANK B. RAE.

Witnesses:

JNO. G. RUMNEY, HENRY F. DE B. CAMERON.A

